The endogenous lectins of the chick blastoderm are present in association with an apolipoprotein in distinct organelles and in the extracellular matrix

Summary Affinity purified preparations of the galactose-binding lectin from gastrulating chick blastoderms consist of three main polypeptides. Two of these have been identified as the 14 kD and 16 kD galactose-binding lectins. A third one migrates in SDS-PAGE gels with a relative molecular weight of 6,500±500 and has been identified as an apolipoprotein (Apo) of plasma very low density lipoproteins, Apo-VLDL-II. We have studied the localization of these polypeptides using immunofluorescence and ultrastructural immunocytochemistry with peroxidase and protein-A gold. The 14 kD lectin occurs in the intracellular yolk where it is mainly present within the electron lucent component. The 16 kD is also present in the intracellular yolk platelets, but tends to predominate in the electron-dense component. In addition, the 16 kD lectin is also present in pleiomorphic yolk-associated organelles and in the extracellular matrix. Apo-VLDL-II is also localized in the electron-lucent component of the yolk platelet and in the extracellular matrix. Our results suggest that the lectin(s) are associated with Apo-VLDL-II in the yolk platelet, and may subsequently become externalized.     

Identification of some lactic acid bacteria from two Zimbabwean fermented milk products

Ten predominant lactic acid bacterial isolates from traditionally fermented milk and four isolates from an industrially fermented milk, Lacto, together with 14 reference strains ofLactobacillus and three ofLactococcus were examined for 32 characteristics. Data were analysed using the simple matching coefficient and clustering was by unweighted pair group average linkage. All the isolated from traditionally fermented milk belonged to the genusLactobacillus. Seven isolates could be identified as belonging toL. helveticus, L. plantarum, L. delbrueckii subsp.lactis, L. casei subsp.casei andL. casel subsp.pseudoplantarum. Three of the isolates could only be identified as either betabacteria or streptobacteria. The four isolates from Lacto were identified asLactococcus lactis. However, they could not be identified to subspecies level.

---

Résumé On a examiné 32 caractéristiques de 10 souches de bactéries lactiques isolées de fait fermenté de manière traditionnelle, et de 4 souches isolées d'un lait fermenté industriel, le Lacto, ainsi que 14 souches de référence deLactobacillus et trols deLactococcus. Les données ont été analysées en utilisant le coefficient d'apparienient simple et le groupement par lien moyen de groupe pair non balancé. Toutes les souches isolées du lait fermenté de manfère traditionnelle appartiennent au genteLactobacillus. Sept souches ont pu étre identifiées comme appartenant àL. helveticus, L. plantarum, L. delbruckii subsp.lactis, L. casei subsp.casei etL. casei subsp.pseudoplantarum. Trois de ces souches n'ont pu être identifiées soit comme bétabactéries soit comme streptobactéries. Les quatres souches isolées de Lacto ont été identifiées commeLactococcus lactis. Celles-ci n'ont toutefois pas pu être identifiées jusqu'au stade de sous-espèce.

     

What is Unique About Superoxide Toxicity as Compared to Other Biological Reductants? — A Hypothesis

Usually the toxicity of superoxide is attributed lo its ability to reduce metal ions and subsequently reoxidation of the metal by hydrogen peroxide yields deleterious oxidizing species. As many other nontoxic biological reductants reduce metal compounds, we suggest that part of the mechanism of superoxide toxicity results from its ability to oxidize metal ions bound to biological targets, which subsequently degrade the target via an intramolecular electron Transfer reaction.     

Molecular analysis of yellow fever virus 17DD vaccine strain.

The Oswaldo Cruz Foundation produces most of the yellow fever (YF) vaccine prepared worldwide. As part of a broader approach to determine the genetic variability in YF 17D seeds and vaccines and its relevance to viral attenuation the 17DD virus was purified directly from chick embryo homogenates which is the source of virus used for vaccination of millions of people in Brazil and other countries for half a century. Neutralization and hemagglutination tests showed that the purified virus is similar to the original stock. Furthermore, radioimmune precipitation of 35S-methionine-labeled viral proteins using mouse hyperimmune ascitic fluid revealed identical patterns for the purified 17DD virus and the YF 17D-204 strain except for the 17DD E protein which migrated slower on SDS-PAGE. This difference is likely to be due to N-linked glycosylation. Finally, comparison by northern blot hybridization of virion RNAs of purified 17DD with two other strains of YF 17D virus revealed only genome-sized molecules for all three viruses. These observations suggest that the vaccine phenotype is primarily associated with the accumulation of mutations.     

Steroid bioconversion in a novel aqueous two-phase system

A novel aqueous two-phase system, based on polyethyleneglycol (PEG) and monosodium glutamate, was tested for the 1-dehydrogenation of hydrocortisone-based substrates. This system led to higher substrate solubilities and biocatalyst/steroid separation levels when compared with alternative systems. The addition of short-chain monohydric alcohols resulted in higher solubilities and more favourable partition coefficients for the tested substrates. Bioconversion activities in PEG/glutamate systems with 2,5% (v/v) methanol were comparable to those measured in monophasic buffer-methanol medium.     

Candida albicans and three other Candida species contain an elongation factor structurally and functionally analogous to elongation factor 3.

A cell-free poly(U)-dependent translation elongation system from Candida albicans is ATP-dependent due to the presence of an elongation factor 3 (EF3)-like activity. Saccharomyces cerevisiae ribosomes added to a C. albicans postribosomal supernatant (PRS) supported poly(U)-dependent elongation, suggesting that the C. albicans lysate contained a soluble translation factor functionally analogous to the S. cerevisiae translation factor EF-3. The presence of EF-3 in C. albicans was confirmed by Western blotting using an antibody raised against S. cerevisiae EF-3. This antibody was also used to screen a selection of Candida species, all of which possessed EF-3 with molecular mass in the range of 110-130 kDa.     

Nonaspiration fine needle cytology. Application of a new technique to nodular thyroid disease

The basic principle underlying fine needle aspiration (FNA) is the aspiration of cellular material from target masses, often utilizing fairly high suction pressures. The procedure requires a needle and a syringe, advisedly held in a syringe holder, enabling single-handed suction to be exercised. Mastery of the technique is variable, with few operators acquiring consistent skill. A new technique, pioneered in France but essentially unpublicized, eliminates active aspiration, replacing it by the principle of capillary suction of fluid or semifluid material into a thin channel (a fine needle). This nonaspiration sampling method was tested in a consecutive series of 50 solid thyroid nodules. Simultaneously performed conventional FNAs served as controls. Cell samples were cytologically assessed as unsuitable, diagnostic/adequate or diagnostic/superior, without knowledge of the sampling method employed. Diagnostically superior specimens were obtained significantly more frequently by the nonaspiration technique in 36 benign lesions and 13 neoplasms. The method of nonaspiration fine needle cytology ("cytopuncture") is described and illustrated, and the implications for its use in other sites are discussed.     

Fruiting at High Temperature and Its Genetic Control in the Basidiomycete Flammulina velutipes

Of 10 geographic strains of Flammulina velutipes, 4 were found capable of fruiting at 22°C (Fr_H) rather than at the typical 15°C (Fr_L). Crosses made between Fr_H and Fr_L monokaryons were never observed to fruit at 22°C. However, some hybrids did fruit at the intermediate temperature of 18°C when grown on appropriate substrates, indicating incomplete dominance of the low-temperature requirement. Analysis of progeny of five Fr_H × Fr_L crosses indicated that a minimum of two genes appears to control the requirement for fruiting at ≤15°C. The genes are not closely linked to either incompatibility locus.     

Holozygosity for sex-linked genes in males of the termiteIncisitermes schwarzi

The termite Incisitermes schwarzi has multiple sex chromosomes that have arisen by repeated translocations between autosomes and previously existing sex chromosomes. Two sex-linked allozyme loci--Acp-1 and Est-3--are holozygous, not hemizygous, in males (the heterogametic sex). Both loci show less than 1% crossing-over between X and Y chromosomes, and alleles of both are in marked disequilibrium with respect to X vs Y linkage. The two loci assort independently in female meiosis, indicating that they lie on different sex chromosomes. But they are tightly linked in male meiosis because of nonrandom assortment of the multiple X and Y chromosomes in males of this species. The findings of holozygosity and strong linkage disequilibrium suggest that differential selection in the two sexes at or near these loci may be responsible for the establishment of the translocations in this species. The existence of active Y-linked alleles also suggests that the translocations may have occurred recently.     

Initial stages in the course of adventitious bud formation on embryos of Picea abies

Adventitious buds on embryos of Picea abies (L.) Karst. developed after a pulse treatment with 250 μ M benzyladenine (BA) of pH 5.5 for 2 h. Light and temperature regimes were not critical during the initial stages. Adventitious buds developed faster after a pulse treatment and the variation among different experiments was lower compared to when the embryos were cultured on media supplemented with BA. Various stages of the differentiation of adventitious buds were identified: stage 1 - appearance of meristematic centres (approximately the first two weeks); stage 2 - development of adventitious bud primordia (approximately the third week); stage 3 - adventitious bud development (from approximately the 4th to the 8th week). This system may be used for further studies on bud differentiation.